| 摘要 |
PROBLEM TO BE SOLVED: To prevent the size reduction of the zoom lens from being impeded by controlling lens positions on the basis of the focal length at which the minimum lens interval is obtained so that the focus surface position of the other focal length is aligned with the focus surface position of the former focal length. SOLUTION: Pulsers P1 to P4 detect the positions of 1st to 4th lens groups L1 to L4 of the zoom lens 10 and a focal length detecting mechanism 11 detects the focal length of the zoom lens 10. The lens groups L1 to L2 gradually increase the interval from a long-focal-length end (L end) to a short-focal-length end (S end) and the lens groups L1 and L2 are at the minimum interval at the L end. The lens group L1 or L2 serves as a zoom adjusting lens group which moves a focus surface position to make a zoom adjustment for aligning the focus surface position of the other focal length and a back adjustment for aligning the aligned focus surface position with an image pickup surface R, on the basis of the focus surface position at the L end as a reference position. |
